We studied the significance of peritoneal cytology as a prognostic factor in primary epithelial ovarian cancer. Intraperitoneal specimens for cytological examination were taken from 73 patients at primary operation for ovarian cancer. The prognostic value of cytological findings was analyzed by the Kaplan-Meier method. It was also correlated to clinical stage, tumor histology, histopathological grade, residual tumor, presence of ascites and age by using the chi2-test. The value of cytology in relation to other factors was assessed by Cox-multivariate analysis. In univariate analysis peritoneal cytological findings correlated significantly to survival. In Cox-multivariate analysis peritoneal cytology, histopathological grade and the age of the patient were found to be significant independent prognostic factors in epithelial ovarian cancer. According to this data peritoneal cytology can be considered as an important prognostic factor in ovarian cancer. Therefore it should be evaluated routinely in association with surgery of ovarian tumors.